An Analytical Model for Hardened Latch Selection and Exploration

Hardened flip-flops and latches are designed to be resilient to soft errors, maintaining high system reliability in the presence of energetic radiation. The wealth of different hardened designs (with varying protection levels) and the probabilistic nature of reliability complicates the choice of which hardened storage element to substitute where. This paper develops an analytical model for hardened latch and flip-flop design space exploration. It is shown that the best hardened design depends strongly on the target protection level and the chip that is being protected. Also, the use of multiple complementary hardened cells can combine the relative advantages of each design, garnering significant efficiency improvements in many situations.